Re: HYB:double fertilization

Double fertilization refers to the process that takes place in every seed
plant. Each pollen grain contains 2 sperm nuclei. One of them fertilizes
the egg nucleus, which produces the embryo plant. The other fuses with two
additional nuclei in the ovule to produce the endosperm tissue, which stores
food in the seed (yes, the endosperm tissue is thereby triploid!).
If mixed pollen is applied to a stigma, it is possible for the seeds in the
resulting pod to have different pollen parents. Each ovule fertilization
event is separate. That means there has to be at least one pollen grain for
each seed produced; no more than single ovule can be fertilized by a single
pollen grain.
Bill Shear
Department of Biology
Hampden-Sydney College
Hampden-Sydney VA 23943
(434)223-6172
FAX (434)223-6374
email<wshear@email.hsc.edu>
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